What is Santorum's path forward?

Former Sen. Rick Santorum's strong showing in Iowa doesn't guarantee him momentum in New Hampshire.

Story highlights

Rick Santorum has a tough challenge translating his momentum into post-Iowa success

Santorum likely needs to do well in New Hampshire and finish first in South Carolina

The GOP is sharply split between business pragmatists and more rigid social conservatives

Romney still has to prove he can win over more than 25% or 30% of GOP voters

Congratulations are in order for Rick Santorum. The former Pennsylvania senator rose from the ranks of the political dead Tuesday night to come within eight votes of a first-place Iowa finish. Saying he defied expectations could be the biggest understatement of the 2012 election cycle so far.

But where does Santorum go from here? And what does his virtual Iowa tie with frontrunner Mitt Romney say about the state of the Republican Party?

The short answer to the first question, according to analysts, is that Santorum probably needs to finish strong in moderate New Hampshire on January 10 and top the field in conservative South Carolina on January 21. If Santorum can knock the former Massachusetts governor off his stride -- however long the odds -- we could have a more serious nomination fight on our hands.

As for the second question, we're looking at a severely fractured GOP.

"The general electorate is now seeing the stark divisions within the GOP up close and personal," says Brown University political scientist Wendy Schiller. "Libertarian, social conservative, and fiscal conservative. Will the real GOP stand up?"

Exit polls in Iowa showed a party largely split between its more pragmatic, business-oriented base and conservative religious voters that provide the bulk of the party's grass-roots muscle. Romney's the candidate of the establishment, diminished though it may be. Santorum's the favorite of religious and tea party conservatives.

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Specifically, in Iowa Romney ran best among voters most concerned with defeating President Barack Obama in November. The former venture capitalist was also the favorite among the majority of caucus-goers who said business experience is more important than a government background.

For his part, the adamantly anti-abortion Santorum ran best among the Iowa GOP's powerful born-again and evangelical voters -- nearly 60% of the Iowa electorate. He also ran strongest among the nearly half of caucus-goers who described themselves as very conservative.

Santorum topped the field among the 65% of voters who feel positive about the populist tea party movement.

There was also a split along financial lines, with Romney running best among voters making more than $50,000 a year. Santorum and Texas Rep. Ron Paul did better among voters making less.

"Usually Republican races have not fallen along those lines but there's a real possibility you will see that class divide in the Republican Party, because Mitt Romney is a very strong candidate for the upper middle class Republicans," political analyst Ron Brownstein told CNN. "They relate to him as a manager and business guy. He's struggled more with the blue collar components."

Santorum, on the other hand, excels at "both cultural conservative and economic nationalism aimed directly at those voters. "

Can Santorum translate his support into the kind of campaign capable of challenging Romney's financial and organizational edge?

Santorum's model, according to Northeastern University political scientist Bill Mayer, should probably be similar to Gary Hart's path in 1984. Hart didn't win the Democratic Party's nod that year, but he used a better-than-expected showing in Iowa to win New Hampshire and create a far more serious contest than most observers expected.

But "it's by no means certain that Santorum will get a bounce out of Iowa," Mayer warned. Multiple candidates have won Iowa, only to fall short in New Hampshire, including George W. Bush in 2000, Bob Dole in 1988 and 1996, and Dick Gephardt in 1988.

John Edwards finished a close second in Iowa in 2004, but gained virtually no traction in the Granite State.

"New Hampshire is quite conservative on economic issues, but quite liberal on social issues. It really meets the old stereotype of the traditional Yankee conservative," Mayer said.

Santorum will have far fewer evangelical or hardline conservative voters to depend on in New Hampshire, he stressed.

As for bypassing New Hampshire and holding out for South Carolina, momentum "tends to be a short-lived commodity" in nomination fights, Mayer warned. Iowa will be ancient history by the time January 21 rolls around.

Rick Perry's decision Wednesday to stay in the race and campaign hard in South Carolina also complicates matters for Santorum, who would benefit from a less divided pool of Palmetto State social conservatives.

Santorum may actually be auditioning for the vice presidential slot, argued Schiller.

Since Santorum "can't claim to bring Pennsylvania with him -- he lost his last re-election bid there -- he has decided to consolidate the very social conservative and activist wing of the GOP behind him," Schiller said. Santorum's ability to do so may "show Romney that if he wants those folks to get out and vote on Election Day (in November), Romney needs Santorum on the ticket. "

Schiller also noted that "the longer Santorum can stay in ... the more he can lay claim to being properly vetted (unlike Sarah Palin) and the more he can start to look like he belongs on the ticket. "

Romney, however, still has a few questions of his own that need to be answered. For all the talk of his frontrunner status, Romney didn't do much better in Iowa in 2012 than he did in 2008, at least in terms of overall vote share. The former governor has yet to prove that he can break a national ceiling of between 25% and 30% support among Republicans.

There are "still a lot of Republicans that are less than thrilled with his candidacy," Mayer said. Romney's fear all along has been that some kind of "relatively plausible alternative candidate emerges. He's been fortunate that there aren't a lot of other strong candidates in this field."

But the Iowa caucuses are noted for their low turnout and are "very heavily weighted toward the types of people that tend to be most skeptical of Romney," Mayer noted. Going forward, the most likely Romney skeptics will not comprise nearly as large a share of the GOP electorate, he said.